netdev - Re: [PATCH net-next 1/2] ipv6: add ipv6_fragment hook in ipv6

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Message-ID: <20200827223836.GB2443@localhost.localdomain>
Date:   Thu, 27 Aug 2020 19:38:36 -0300
From:   Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     wenxu@...oud.cn, netdev@...r.kernel.org
Subject: Re: [PATCH net-next 1/2] ipv6: add ipv6_fragment hook in ipv6_stub

On Thu, Aug 27, 2020 at 07:51:47AM -0700, David Miller wrote:
> From: wenxu@...oud.cn
> Date: Thu, 27 Aug 2020 18:39:51 +0800
> 
> > From: wenxu <wenxu@...oud.cn>
> > 
> > Add ipv6_fragment to ipv6_stub to avoid calling netfilter when
> > access ip6_fragment.
> > 
> > Signed-off-by: wenxu <wenxu@...oud.cn>
> 
> Please test these changes with ipv6 disabled.
> 
> It will crash, you have to update the default stub in
> net/ipv6/addrconf_core.c as well.

I didn't test it myself but I'm not seeing how the crash could happen.
The next patch does check for it being NULL before using it:

-               if (!v6ops)
+               if (!ipv6_stub->ipv6_fragment)
                        goto err;

Wenxu?

  Marcelo